When he was still a student at USC in 2005, Levie emailed Cuban to tell him about his company. Cuban liked the idea and offered to make a $350,000 seed investment. Levie took the money.

A year after the investment, Cuban wanted out of the company.

Levie wanted to give away a gigabyte of storage to get as many users as possible. He would charge when they went above that limit. He feared that Google or Yahoo was going to come out with a rival product that would crush Box.

Cuban disagreed with this plan. He wanted Box to keep charging customers. Levie told design agency Zurb, "Mark didn't like that as an idea because it meant that we would need to go on and take more funding and subsidize the user base initially through venture capital. He liked the neat and tidiness of a very linear, understandable business model."

When Levie raised his next round of funding, he used a portion of the money to buy back Cuban's stake.

By ditching his investment so early, Cuban missed out on a giant windfall. Box's latest valuation has the company at $2 billion. As a seed investor, Cuban was poised to have a big return.

Cuban talked about the Box IPO on Twitter last night. And he hinted that he stands by his decision to get out of the company.

Box's S-1 revealed that it generated $124 million in revenue last year while racking up losses of $168 million. Cuban says that if he were responsible for those numbers he would "combust":

I wish @BoxHQ the best but I would combust if 8 years in I was responsible for $169mm in losses against less revs.I hope IPO gets them going — Mark Cuban (@mcuban) March 25, 2014